<script>
import {
  closest, getOffset, getPrecedingRange,
  getRange, applyRange,
  scrollIntoView, getAtAndIndex
} from './util'
import AtTemplate from './AtTemplate.vue'

export default {
  name: 'VueAt',
  mixins: [AtTemplate],
  emits: ['update:value', 'at', 'insert'],
  props: {
    value: {
      type: String, // value not required
      default: null
    },
    at: {
      type: String,
      default: null
    },
    ats: {
      type: Array,
      default: () => ['@']
    },
    suffix: {
      type: String,
      default: ' '
    },
    loop: {
      type: Boolean,
      default: true
    },
    allowSpaces: {
      type: Boolean,
      default: true
    },
    tabSelect: {
      type: Boolean,
      default: false
    },
    avoidEmail: {
      type: Boolean,
      default: true
    },
    showUnique: {
      type: Boolean,
      default: true
    },
    hoverSelect: {
      type: Boolean,
      default: true
    },
    members: {
      type: Array,
      default: () => []
    },
    nameKey: {
      type: String,
      default: ''
    },
    filterMatch: {
      type: Function,
      default: (name, chunk, at) => {
        // match at lower-case
        return name.toLowerCase()
          .indexOf(chunk.toLowerCase()) > -1
      }
    },
    deleteMatch: {
      type: Function,
      default: (name, chunk, suffix) => {
        return chunk === name + suffix
      }
    },
    scrollRef: {
      type: String,
      default: ''
    }
  },

  data () {
    return {
      // at[v-model] mode should be on only when
      // initial :value/v-model is present (not nil)
      bindsValue: this.value != null,
      customsEmbedded: false,
      hasComposition: false,
      atwho: null
    }
  },
  computed: {
    atItems () {
      return this.at ? [this.at] : this.ats
    },

    currentItem () {
      if (this.atwho) {
        return this.atwho.list[this.atwho.cur]
      }
      return ''
    },

    style () {
      if (this.atwho) {
        const { list, cur, x, y } = this.atwho
        const { wrap } = this.$refs
        if (wrap) {
          const offset = getOffset(wrap)
          const scrollLeft = this.scrollRef ? document.querySelector(this.scrollRef).scrollLeft : 0
          const scrollTop = this.scrollRef ? document.querySelector(this.scrollRef).scrollTop : 0
          const left = x + scrollLeft + window.pageXOffset - offset.left + 'px'
          const top = y + scrollTop + window.pageYOffset - offset.top + 'px'
          return { left, top }
        }
      }
      return null
    }
  },
  watch: {
    'atwho.cur' (index) {
      if (index != null) { // cur index exists
        this.$nextTick(() => {
          this.scrollToCur()
        })
      }
    },
    members () {
      this.handleInput(true)
    },
    value (value, oldValue) {
      if (this.bindsValue) {
        this.handleValueUpdate(value)
      }
    }
  },
  mounted () {
    // vue3 migration.5
    // [Vue warn]: (deprecation INSTANCE_SCOPED_SLOTS) vm.$scopedSlots has been removed. Use vm.$slots instead.
    // Details: https://v3-migration.vuejs.org/breaking-changes/slots-unification.html
    if (this.$slots.embeddedItem) {
      this.customsEmbedded = true
    }
    if (this.bindsValue) {
      this.handleValueUpdate(this.value)
    }
  },

  methods: {
    itemName (v) {
      const { nameKey } = this
      return nameKey ? v[nameKey] : v
    },
    isCur (index) {
      return index === this.atwho.cur
    },
    handleValueUpdate (value) {
      const el = this.$el.querySelector('[contenteditable]')
      if (value !== el.innerHTML) { // avoid range reset
        el.innerHTML = value
        this.dispatchInput()
      }
    },
    dispatchInput () {
      let el = this.$el.querySelector('[contenteditable]')
      let ev = new Event('input', { bubbles: true })
      el.dispatchEvent(ev)
    },

    handleItemHover (e) {
      if (this.hoverSelect) {
        this.selectByMouse(e)
      }
    },
    handleItemClick (e) {
      this.selectByMouse(e)
      this.insertItem()
    },
    handleDelete (e) {
      const range = getPrecedingRange()
      if (range) {
        // fixme: Very bad code from me
        if (this.customsEmbedded && range.endOffset >= 1) {
          let a = range.endContainer.childNodes[range.endOffset] ||
            range.endContainer.childNodes[range.endOffset - 1]
          if (!a || a.nodeType === Node.TEXT_NODE && !/^\s?$/.test(a.data)) {
            return
          } else if (a.nodeType === Node.TEXT_NODE) {
            if (a.previousSibling) a = a.previousSibling
          } else {
            if (a.previousElementSibling) a = a.previousElementSibling
          }
          let ch = [].slice.call(a.childNodes)
          ch = [].reverse.call(ch)
          ch.unshift(a)
          let last
          ;[].some.call(ch, c => {
            if (c.getAttribute && c.getAttribute('data-at-embedded') != null) {
              last = c
              return true
            }
          })
          if (last) {
            e.preventDefault()
            e.stopPropagation()
            const r = getRange()
            if (r) {
              r.setStartBefore(last)
              r.deleteContents()
              applyRange(r)
              this.handleInput()
            }
          }
          return
        }

        const { atItems, members, suffix, deleteMatch, itemName } = this
        const text = range.toString()
        const { at, index } = getAtAndIndex(text, atItems)

        if (index > -1) {
          const chunk = text.slice(index + at.length)
          const has = members.some(v => {
            const name = itemName(v)
            return deleteMatch(name, chunk, suffix)
          })
          if (has) {
            e.preventDefault()
            e.stopPropagation()
            const r = getRange()
            if (r) {
              r.setStart(r.endContainer, index)
              r.deleteContents()
              applyRange(r)
              this.handleInput()
            }
          }
        }
      }
    },
    handleKeyDown (e) {
      const { atwho } = this
      if (atwho) {
        if (e.keyCode === 38 || e.keyCode === 40) { // ↑/↓
          if (!(e.metaKey || e.ctrlKey)) {
            e.preventDefault()
            e.stopPropagation()
            this.selectByKeyboard(e)
          }
          return
        }
        if (e.keyCode === 13 || (this.tabSelect && e.keyCode === 9)) { // enter or tab
          e.preventDefault()
          e.stopPropagation()
          this.insertItem()
          return
        }
        if (e.keyCode === 27) { // esc
          this.closePanel()
          return
        }
      }

      // 为了兼容ie ie9~11 editable无input事件 只能靠keydown触发 textarea正常
      // 另 ie9 textarea的delete不触发input
      const isValid = e.keyCode >= 48 && e.keyCode <= 90 || e.keyCode === 8
      if (isValid) {
        setTimeout(() => {
          this.handleInput()
        }, 50)
      }

      if (e.keyCode === 8) {
        this.handleDelete(e)
      }
    },

    // compositionStart -> input -> compositionEnd
    handleCompositionStart () {
      this.hasComposition = true
    },
    handleCompositionEnd () {
      this.hasComposition = false
      this.handleInput()
    },
    handleInput (keep) {
      if (this.hasComposition) return
      const el = this.$el.querySelector('[contenteditable]')

      // vue3 migration.2.1
      // https://vuejs.org/guide/components/events.html#usage-with-v-model
      // https://laracasts.com/discuss/channels/vue/how-do-emit-to-v-model-in-vue-3
      // this.$emit('input', el.innerHTML)
      this.$emit('update:value', el.innerHTML)

      const range = getPrecedingRange()

      if (range) {
        if (keep) {
          // exit the function if the range is not inside this.$el
          let container = range.commonAncestorContainer;
          while (container) {
            if (container === this.$el) break;
            container = container.parentElement;
          }
          if (!container) return;
        }

        const { atItems, avoidEmail, allowSpaces, showUnique } = this

        let show = true
        const text = range.toString()

        const { at, index } = getAtAndIndex(text, atItems)

        if (index < 0) show = false
        const prev = text[index - 1]

        const chunk = text.slice(index + at.length, text.length)

        if (avoidEmail) {
          // 上一个字符不能为字母数字 避免与邮箱冲突
          // 微信则是避免 所有字母数字及半角符号
          if (/^[a-z0-9]$/i.test(prev)) show = false
        }

        if (!allowSpaces && /\s/.test(chunk)) {
          show = false
        }

        // chunk以空白字符开头不匹配 避免`@ `也匹配
        if (/^\s/.test(chunk)) show = false

        if (!show) {
          this.closePanel()
        } else {
          const { members, filterMatch, itemName } = this
          if (!keep && chunk) { // fixme: should be consistent with AtTextarea.vue
            this.$emit('at', chunk)
          }
          const matched = members.filter(v => {
            const name = itemName(v)
            return filterMatch(name, chunk, at, v)
          })

          show = false
          if (matched.length) {
            show = true
            if (!showUnique) {
              let item = matched[0]
              if (chunk === itemName(item)) {
                show = false
              }
            }
          }

          if (show) {
            this.openPanel(matched, range, index, at)
          } else {
            this.closePanel()
          }
        }
      }
    },

    closePanel () {
      if (this.atwho) {
        this.atwho = null
      }
    },
    openPanel (list, range, offset, at) {
      const fn = () => {
        const r = range.cloneRange()
        r.setStart(r.endContainer, offset + at.length) // 从@后第一位开始
        // todo: 根据窗口空间 判断向上或是向下展开
        const rect = r.getClientRects()[0]
        this.atwho = {
          range,
          offset,
          list,
          x: rect.left,
          y: rect.top - 4,
          cur: 0 // todo: 尽可能记录
        }
      }
      if (this.atwho) {
        fn()
      } else { // 焦点超出了显示区域 需要提供延时以移动指针 再计算位置
        setTimeout(fn, 10)
      }
    },

    scrollToCur () {
      // vue3 migration.6
      // fix: [Vue warn]: Missing ref owner context. ref cannot be used on hoisted vnodes.
      // A vnode with ref must be created inside the render function.
      // at selectByMouse
      // at handleItemHover
      // const curEl = this.$refs.cur[0]
      let { wrap } = this.$refs
      let { cur } = this.atwho
      const curEl = wrap.querySelector(`.atwho-li[data-index="${cur}"]`)

      const scrollParent = curEl.parentElement.parentElement // .atwho-view
      scrollIntoView(curEl, scrollParent)
    },
    selectByMouse (e) {
      const el = closest(e.target, d => {
        return d.getAttribute('data-index')
      })
      const cur = +el.getAttribute('data-index')
      this.atwho = {
        ...this.atwho,
        cur
      }
    },
    selectByKeyboard (e) {
      const offset = e.keyCode === 38 ? -1 : 1
      const { cur, list } = this.atwho
      const nextCur = this.loop
        ? (cur + offset + list.length) % list.length
        : Math.max(0, Math.min(cur + offset, list.length - 1))
      this.atwho = {
        ...this.atwho,
        cur: nextCur
      }
    },

    // todo: 抽离成库并测试
    insertText (text, r) {
      r.deleteContents()
      const node = r.endContainer
      if (node.nodeType === Node.TEXT_NODE) {
        const cut = r.endOffset
        node.data = node.data.slice(0, cut) +
          text + node.data.slice(cut)
        r.setEnd(node, cut + text.length)
      } else {
        const t = document.createTextNode(text)
        r.insertNode(t)
        r.setEndAfter(t)
      }
      r.collapse(false) // 参数在IE下必传
      applyRange(r)
      this.dispatchInput()
    },

    insertHtml (html, r) {
      r.deleteContents()
      const node = r.endContainer
      const newElement = document.createElement('span')

      // Seems `contentediable=false` should includes spaces,
      // otherwise, caret can't be placed well across them
      newElement.appendChild(document.createTextNode(' '))
      newElement.appendChild(this.htmlToElement(html))
      newElement.appendChild(document.createTextNode(' '))
      newElement.setAttribute('data-at-embedded', '')
      newElement.setAttribute('contenteditable', false)

      if (node.nodeType === Node.TEXT_NODE) {
        const cut = r.endOffset
        let secondPart = node.splitText(cut)
        node.parentNode.insertBefore(newElement, secondPart)
        r.setEndBefore(secondPart)
      } else {
        const t = document.createTextNode(this.suffix)
        r.insertNode(newElement)
        r.setEndAfter(newElement)
        r.insertNode(t)
        r.setEndAfter(t)
      }
      r.collapse(false) // 参数在IE下必传
      applyRange(r)
    },

    insertItem () {
      const { range, offset, list, cur } = this.atwho
      const { suffix, atItems, itemName, customsEmbedded } = this
      const r = range.cloneRange()
      const text = range.toString()
      const { at, index } = getAtAndIndex(text, atItems)

      // Leading `@` is automatically dropped as `customsEmbedded=true`
      // You can fully custom the output inside the embedded slot
      const start = customsEmbedded ? index : index + at.length
      r.setStart(r.endContainer, start)

      // hack: 连续两次 可以确保click后 focus回来 range真正生效
      applyRange(r)
      applyRange(r)
      const curItem = list[cur]

      if (customsEmbedded) {
        // `suffix` is ignored as `customsEmbedded=true` has to be
        // wrapped around by spaces

        // vue3 migration.7
        // fix: Uncaught TypeError: Cannot read properties of undefined (reading 'innerHTML')
        // at Proxy.insertItem (At.vue?075e:490:1)
        // at Proxy.handleItemClick (At.vue?075e:184:1)
        // const html = this.$refs.embeddedItem.firstChild.innerHTML
        const html = this.$refs.embeddedItem.firstElementChild.innerHTML

        this.insertHtml(html, r)
      } else {
        const t = itemName(curItem) + suffix
        this.insertText(t, r)
      }
      scrollIntoView(window.getSelection())

      this.$emit('insert', curItem)
      this.handleInput()

      // fix safari: use `r` instead of `window.getSelection()`
      // scrollIntoView(window.getSelection())
      scrollIntoView(r)
    },
    htmlToElement (html) {
      const template = document.createElement('template')
      html = html.trim() // Never return a text node of whitespace as the result
      template.innerHTML = html
      return template.content.firstChild
    }
  }
}
</script>
